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Université de Fribourg

Early diagenetic dolomitization and dedolomitization of Late Jurassic and earliest Cretaceous platform carbonates: A case study from the Jura Mountains (NW Switzerland, E France)

Rameil, Niels

In: Sedimentary Geology, 2008, vol. 212, no. 1-4, p. 70-85

Early diagenetic dolomitization is a common feature in cyclic shallow-water carbonates throughout the geologic record. After their generation, dolomites may be subject to dedolomitization (re-calcification of dolomites), e.g. by contact with meteoric water during emersion. These patterns of dolomitization and subsequent dedolomitization frequently play a key role in unravelling the development...

Université de Fribourg

Formation and spread of callus tissue and tangential rows of resin ducts in Larix decidua and Picea abies following rockfall impacts

Schneuwly, Dominique M. ; Stoffel, Markus ; Bollschweiler, Michelle

In: Tree Physiology, 2009, vol. 29, no. 2, p. 281-289

After mechanical wounding, callus tissue and tangential rows of traumatic resin ducts (TRDs) are formed in many conifer species. This reaction can be used to date past events of geomorphic processes such as rockfall, debris flow and snow avalanches. However, only few points are known about the tangential spread or the timing of callus tissue and TRD formation after wounding. We analyzed 19 Larix...

Université de Fribourg

New ruthenium(II) complexes with enantiomerically pure bis- and tris(pinene)-fused tridentate ligands: synthesis, characterization and stereoisomeric analysis

Sala, Xavier ; Poater, Albert ; Zelewsky, Alexander von ; Parella, Teodor ; Fontrodona, Xavier ; Romero, Isabel ; Solà, Miquel ; Rodríguez, Montserrat ; Llobet, Antoni

In: Inorganic Chemistry, 2008, vol. 47, no. 18, p. 8016–8024

A new set of Ru−Cl complexes containing either the pinene[5,6]bpea ligand (L1) or the C₃ symmetric pinene[4,5]tpmOMe (L2) tridentate ligand in combination with the bidentate (B) 2,2′-bipyridine (bpy) or 1,2-diphenylphosphinoethane (dppe) with general formula [RuCl(L1 or L2)(B)]⁺ have been prepared and thoroughly characterized. In the solid state, X-ray diffraction...

Université de Fribourg

Synthesis of poly(paraphenylene vinylene) - polystyrene-based rod-coil block copolymer by atom transfer radical polymerization: Toward a self-organized lamellar semiconducting material

Brochon, Cyril ; Sary, Nicolas ; Mezzenga, Raffaele ; Ngov, Chheng ; Richard, Fanny ; May, Michaël ; Hadziioannou, Georges

In: Journal of Applied Polymer Science, 2008, vol. 110, no. 6, p. 3664 - 3670

Atom transfer radical polymerization (ATRP) was used as a versatile route to well-defined poly(diethylhexyl-p-phenylenevinylene-b-styrene) (PPV-b-PS) semiconducting block copolymers. For this purpose, original conjugated macroinitiators were synthesized from DEH-PPV and further used for the copolymerization reaction. The microphase-separated morphologies obtained with the semiconducting PPV-b-PS...

Université de Fribourg

Sawdust addition reduces the productivity of nitrogen-enriched mountain grasslands

Spiegelberger, Thomas ; Müller-Schärer, Heinz ; Matthies, Diethart ; Schaffner, Urs

In: Restoration Ecology, 2008///10.1111/j.1526-100X.2008.00424.x

Anthropogenic nutrient enrichment of mountain grasslands has boosted grasses and fast-growing unpalatable plants at the expense of slow-growing species, resulting in a significant loss in biodiversity. A potential tool to reduce nutrient availability and aboveground productivity without destroying the perennial vegetation is carbon (C) addition. However, little is known about its suitability...

Université de Fribourg

Potential contribution of natural enemies to patterns of local adaptation in plants

Crémieux, Lisèle ; Bischoff, Armin ; Šmilauerová, Majka ; Lawson, Clare S. ; Mortimer, Simon R. ; Doležal, Jiří ; Lanta, Vojtěch ; Edwards, Andrew R. ; Brook, Alex J. ; Tscheulin, Thomas ; Macel, Mirka ; Lepš, Jan ; Müller-Schärer, Heinz ; Steinger, Thomas

In: New Phytologist, 2008, vol. 180, no. 2, p. 524 - 533

Genetic differentiation among plant populations and adaptation to local environmental conditions are well documented. However, few studies have examined the potential contribution of plant antagonists, such as insect herbivores and pathogens, to the pattern of local adaptation.Here, a reciprocal transplant experiment was set up at three sites across Europe using two common plant species, Holcus...

Université de Fribourg

The importance of plant provenance and genotypic diversity of seed material used for ecological restoration

Bischoff, Armin ; Steinger, Thomas ; Müller-Schärer, Heinz

In: Restoration Ecology, 2009///doi:10.1111/j.1526-100X.2008.00454.x

The increased translocation of plant species for biodiversity restoration and habitat creation has provoked a debate on provenance and genotypic diversity of the used plant material. Nonlocal provenances are often not adapted to the local environmental conditions, and low population genotypic diversity may result in genetic bottlenecks hampering successful establishment. We tested provenance...

Université de Fribourg

Functional significance of triazine-herbicide resistance in defence of Senecio vulgaris against a rust fungus

Salzmann, Daniel ; Handley, Richard J. ; Müller-Schärer, Heinz

In: Basic and Applied Ecology, 2008, vol. 9, no. 5, p. 577-587

We investigated the functional significance of plant performance (dry mass, photosynthesis) in plant defence (resistance and tolerance) against pathogen infection, and potential negative cross-resistance between herbicide resistance and plant defence against disease. We compared isonuclear triazine-herbicide-resistant (TR) and -susceptible (TS) biotypes of Senecio vulgaris, in the presence and...

Université de Fribourg

Loss of genetic diversity in isolated populations of an alpine endemic Pilosella alpicola subsp. ullepitschii : effect of long-term vicariance or long-distance

Šingliarová, Barbora ; Chrtek, Jindřich ; Mráz, Patrik

In: Plant Systematics and Evolution, 2008, vol. 275, no. 3-4, p. 181-191

Pilosella alpicola subsp. ullepitschii (Asteraceae) is a strictly allogamous, diploid Carpathian endemic. Its distribution range comprises two areas separated by about 600 km. While in the Western Carpathians (Slovakia and Poland) the taxon occurs in numerous sites, only four localities of man-made origin are known from the Eastern and Southern Carpathians (Romania). We used allozyme markers...

Université de Fribourg

A distinct reed bunting dawn song and its relation to extrapair paternity

Suter, Stefan M. ; Ermacora, David ; Rieille, Nadia ; Meyer, Dietrich R.

In: Animal Behaviour, 2009///doi:10.1016/j.anbehav.2008.11.002

Elaborate birdsong is thought to have evolved under sexual selection. Extrapair mating can enforce sexual selection and thus the selection of song traits. We investigated song rate and song diversity, two song traits previously shown to be under sexual selection, in relation to paternity success in the reed bunting, Emberiza schoeniclus, a species with high levels of extrapair paternity. We...